The broth is white because there is milk in it. Chicken stock is let down with milk and seasoned with white miso, soy sauce and sugar, and then chicken and vegetables go in and simmer. It does not smell like a Japanese hot pot. It smells sweet, and faintly of a dairy.

The story goes back to the seventh century, when a monk who had come over from Tang China is said to have made a pot with goat's milk to keep the cold out. Cow's milk is what goes in now. What survived from the story was not the animal but the notion that you could cook a pot in milk at all.

This belongs to Asuka and Kashihara, the old country at the southern end of the Nara basin, where the seventh-century capitals were. Chinese cabbage, white leek, shiitake, potato, carrot, tofu, shirataki. You can dip it in beaten egg the way you would with sukiyaki, or ladle it into a bowl along with its broth and add whatever seasoning is standing on the table.

Nara lies in a basin and the winters there are colder than visitors tend to expect. Put a foreigner in that basin in the seventh century, with no practical way home and a clear memory of how people ate where he came from, and this is an extremely plausible thing to arrive at.